In the practice of medicine and dentistry, audio-visual equipment has been used for presenting programs to a patient to inform or advise the patient in regard to a particular medical or dental problem. For example, audio-visual programs have been used to educate a patient to the potential risks of any surgical procedure and with regard to preparing for a specific surgical operation or caring for a particular area of the body such as the proper way to brush and clean teeth or to use and care for contact lenses. Such audio-visual programs are normally presented to a patient at the physician's office.
It has also been found desirable to use audio-visual equipment for obtaining a patient's medical history with or without requiring an attendant nurse or physician, and for clearly informing a patient or the person responsible for the patient of the details in regard to a particular surgical operation prior to obtaining consent for such operation. In the use of audio-visual programs for obtaining a patient's medical history or for obtaining informed consent for general or specific use, it is necessary to have the patient participate by answering questions presented by an audio-visual program and to analyze answers to the questions in a rapid and efficient manner. In addition, the effectiveness of the informative or educational presentations can be evaluated, by response, for practical and research purposes.
One form of an audio-visual unit which provides desirable features is manufactured and marketed by the North American Phillips Corporation under the trademark of Norelco. The unit is also referred to as the "Pip"audio-visual cassette system and uses separate cassettes for the synchronized audio and visual programs. The visual program is presented by a "super 8"m.m. film roll and the audio tape is recorded with inaudible signals or pulses which control selective advancement of the film. The film may be moved either in increments of one frame or at any rate or multiple of up to 24 frames per second to provide a display of either single frame or natural motion on the viewing screen. A single fifty foot film strip is commonly used in the unit and provides up to 3,600 or more frames for any type program. The audio portion of a program is provided on a tape cassette, thereby presenting pertinent audible narrative.